In a move that has big implications for video game clone claims, a judge has ruled in favor of the Tetris Company against Mino developer Xio Interactive, stating that Mino is substantially similar to Tetris.

Mino was released for iPhone in 2009, and described by the developer as a multiplayer version of Tetris. The Tetris Company filed a lawsuit against Xio later that year, alleging that Mino infringed on its copyrights.

Xio argued that Mino only copied non-protected elements from Tetris, including the rules and functionality of the game, rather than its expressive elements.

However, the U.S. District Court of New Jersey has now ruled that there is a "substantial similarity" between Tetris and Mino, and that Xio has infringed on Tetris Company's copyright. It also stated that Mino constituted unfair competition for Tetris and false endorsement.

The filing explains, "Neither party disputes that a game is deserving of some copyright protection," before adding, "The game mechanics and the rules are not entitled to protection, but courts have found expressive elements copyrightable, including game labels, design of game boards, playing cards and graphical works."

It continues, "Xio is correct that one cannot protect some functional aspect of a work by copyright as one would with a patent. But this principle does not mean, and cannot mean, that any and all expression related to a game rule or game function is unprotectible. Such an exception to copyright would likely swallow any protection one could possibly have; almost all expressive elements of a game are related in some way to the rules and functions of game play."

"Tetris Holding is as entitled to copyright protection for the way in which it chooses to express game rules or game play as one would be to the way in which one chooses to express an idea."